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Monday, December 09, 2024

 

Geminid Meteor Shower 13-15 December 2024

The northern horizon at 3:13 am ACDST as seen from Adelaide on Saturday December 14 when the Geminid radiant is at its highest. The Geminid radiant is marked with a starburst. Similar views will be seen elsewhere in Australia at  a similar latitude and the equivalent local time. (click to embiggen).The northern horizon at 1:46am AEST as seen from Brisbane on on Saturday December 14 when the Geminid radiant is at its highest. The Geminid radiant is marked with a starburst. Similar views will be seen elsewhere in Australia at  a similar latitude and the equivalent local time. (click to embiggen).The northern horizon at 3:17 am AEDST as seen from Melbourne on Saturday December 14 when the Geminid radiant is at its highest. The Geminid radiant is marked with a starburst. Similar views will be seen elsewhere in Australia at  a similar latitude and the equivalent local time. (click to embiggen).


This year is a poor year for the Geminid meteor shower. The Geminids are an unusual meteor shower in that their parent body is 3200 Phaethon, an asteroid, rather than a comet. It is speculated though that Phaeton is actually a "gassed out" comet, and so the debris that makes up the Geminids may still be cometary particles, but is more likely broken rock fragments from its close approach to the sun.

The Geminids are usually a fairly reliable meteor shower but this year there will be significant  interference from the Moon.

The Geminids have a broad peak and normally show good activity well before and after the peak on the day before and after. The nominal peak is December 14, 01h UT, that means in Australia this year most of the activity is concentrated on the morning of the 14th after sunrise, but there will still be decent rates before twilight (although lower this year because of the moonlight).

As the radiant doesn't rise until just before midnight (daylight saving time) in most of Australia and the radiant is highest (with the best meteor rates) in the early hours in a narrow band around 3 am local time, so you are going to lose some sleep for this.  Fortunately this is a Saturday, so you can sleep in after. 


Northern Australians should see a meteor every 1 to 2 minutes under dark skies in the early morning of the 14th. Obviously under suburban skies you will see fewer. 

You can find predictions for your local site at the meteor flux estimator (choose 4 Geminids and date 13-14 December, don't forget to change the date to 2024). You will have to enter your local latitude and longitude for your site. I have also made a table for major cities below.

Unfortunately, both Chrome and Firefox have changed their security settings to prevent plugins from running, and the flux estimator only runs under Internet Explorer now OR Edge in Internet Explorer mode (click on the triple dots once the page has loaded ), you have to have the JAVA plug-in loaded.

You can follow the progress of the shower at the IMO Geminids Live page


At 3.00 am in the morning AEDST (midnight, AEST) Castor (alpha Geminorum) is about four hand-spans above the horizon and almost due north. Pollux, the other twin, is less than a hand-span to the right again and below Castor. The radiant is just below Pollux. The best rates are when the radiant is highest, when it is due north, the Moon is low to the horizon and before astronomical twilight. This is around 3:30 am ACDST Adelaide ~4:00 ACST Darwin, ~3-3:30 am local time Perth and Brisbane and ~ 3:30-4:00 am AEDST Melbourne, Sydney and Hobart.

CityTime Radiant HighestMoon setAstronomical Twilight
Adelaide ACDST3:13
4:18
4:09
Brisbane AEST1:46
3:08
3:14
Darwin ACST2:43
4:43
4:57
Hobart AEDST2:38
3:16
2:39
Melbourne AEDST3:17
4:14
4:00
Perth AWST2:13
3:31
3:25
Sydney AEDST2:52
4:00
3:56


When you get up, allow at least 5 minutes for your eyes to adjust and become dark adapted (even if you have stumbled out of bed in the dark, here's some hints on dark adaption of your eyes so you can see meteors better). 

 
Be patient, it may be several minutes before you are rewarded with you first meteor, then a couple will come along in quick succession (a meteor every 1 to 2 minutes is an average, they won't turn up like a ticking clock but more or less randomly).

Predicted meteor rates for selected towns
 

Locations on the same latitude as...

Morning December 13

Morning December 14 (UT peak)

Morning December 15

Morning December 16

Darwin

19 meteors/hr

48 meteors/hr

11 meteors/hr

2 meteors/hr

Brisbane/Perth

13 meteors/hr

37 meteors/hr

10 meteors/hr

2 meteors/hr

Sydney/Adelaide/Canberra

10 meteors/hr

27 meteors/hr

7 meteors/hr

2 meteors/hr

Melbourne

9 meteors/hr

22 meteors/hr

7 meteors/hr

2 meteors/hr

Hobart

7 meteors/hr

17 meteors/hr

6 meteors/hr

2 meteors/hr

 
 
Locations at similar latitudes to the towns in the list will have similar rates, the more north you are the higher the rate. Choose a viewing spot where you can see a large swathe of sky without trees or buildings getting in the way, or with street lights getting in your eyes. Try and choose a spot where the moon is hidden from view to preserve your night vision.The darker the spot the better (but do be sensible, don't choose a spot in an insalubrious park for example). 
 
While the radiant is where the meteors appear to originate from, most of the meteors will be seen away from the radiant, so don't fixate on the radiant, but keep your eye on a broad swath of sky roughly centered just above the radiant (as the radiant doesn't rise very high, looking exactly at the radiant will mean you miss some higher up).

A lawn chair or something similar will make your observing comfortable (or a picnic rug spread on the ground and a nice pillow), and having a Thermos of hot coffee, tea or chocolate to swig while watching will increase your comfort. Despite it being summer, make sure you have a jumper or something as the night can still get cold. Also, plenty of insect repellent is a good idea.

Guides to taking meteor photos are here and here.

As well, Orion and the Hyades will be visible, with Jupiter in the Hyades and Mars Not far from Castor and Pollux. . So it will be a quite nice morning for sky watching. Keep an eye out for satellites! There may be a bright ISS pass on the morning of the 15th from your location.

Cloud cover predictions can be found at SkippySky.  

Here is the near-real time satellite view of the clouds (day and night) http://satview.bom.gov.au/

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Comments:
I appreciate you doing all this work
 
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